This is a bit more involved than that. This presumably needs to happen within the corresponding AI. When the AI begins it's job you calculate the angle. Then each tick you do angle = angle + NUM(you need to figure out the NUM yourself but effectively this is the speed of circling) and do the rest of the movement-related actions.
Don't directly access the registry, register your things in the appropriate RegistryEvent.Register, in this case it would be Register<Block>.
In case of IHasModel - get rid of it and just register your models directly in the ModelRegistryEvent.
Forge 1.12.2-14.23.5.2779 deprecated ReflectionHelper and changed the methods in ObfuscationReflectionHelper to only require an SRG name rather than both an SRG and MCP name. This is what @quadraxis was talking about.
findField calls setAccessible(true) itself, it doesn't need to be called here at all.
Also, update Forge and use ObfuscationReflectionHelper.findField with only the SRG name (field_184560_g).